Doctors are warning respiratory and heart patients Tuesday to be careful during the heat wave.

Not only does intense heat make air harder to breathe, it also creates problems because lack of circulation means higher levels of toxins like nitric oxides stay afloat longer. When the toxins are breathed in they cause the lungs to become irritated. Norwalk Hospital's Dr. Jonathan Fine says the harsh chemicals can work their way deep into the lungs.

Experts also warn that this kind of weather usually brings excess deaths. They advise people to stay indoors, in air conditioning, especially when exercising. Dr. Fine predicts that because of prolonged heat conditions there may be even higher levels of toxic pollutants in the air Wednesday.